The semiconductor industry has undergone exponential growth, constantly progressing in the aim of higher density, device performance and lower costs. Apart from the classical planar transistor such as a metal-oxide-semiconductor field-effect transistor (MOSFET), various non-planar transistors or three-dimensional (3D), such as a fin-like field-effect transistor (FinFET), have been developed to achieve even higher device density as well as to optimize the device efficacy. The fabrication of both planar and 3D FETs is focused on dimension scaling down to increase the packing density of the semiconductor device.
With increasing demands for high-density integration of the planar and 3D FETs, the fabricating method of FinFETs is in great need to be continuously refined so as to attain a more enhanced semiconductor structure.